Selecting a Cast Process

Selecting a metal casting process is not as simple as selecting the “cheapest” per part price. For a variety of reasons (some discussed below) other casting processes may be a better choice. Precise Cast offers three possible alternatives to aluminum, zinc and magnesium die casting:

Considerations when selecting a production metal casting process include:

Cost – Die cast parts are generally one of the cheapest “per part” options available. However, when the cost of the tooling is factored in, it usually takes a large number of parts for die casting to “break even” with other available processes.

Timing/Speed – How soon are the parts needed? Machined parts can be available in 1-5 days. Plaster casting and sand casting can often yield parts in 1-2 weeks. Die cast parts often take a minimum of 8-12 weeks (usually 12+ weeks).

The geometry and size of the part – See the table below for our casting process capabilities.

The quantities required in a given timeframe – “High quantity” means different things to different people. It also is dependent on “how many parts do you need, and in what timeframe?” 12,000 parts in one batch is very different than 500 parts per month over two years. Due to up-front capital requirements and project budgets, it may be more desirable to pay more for each part and (much) less for the up-front tooling.

The finish required on the part – some parts require a very smooth finish: others may not.

The strength required of the part – Metal parts are, by their nature,“strong”. Stronger is not always better. Each process yields parts with different strength, elongation, internal stress, and other physical characteristics. The process selected should be chosen according to how it meets all of the requirements.

The thermal characteristics required of the part – Each casting process has a group of alloys that are best suited for that process. These alloys have different thermal characteristics. See the Metal Casting Physical Properties table for more information.

There is no “right” answer for every casting situation. If there’s one overriding want or need, that might tip the selection in one direction or another. Even if a process doesn’t rank highest in any one category, the overall combination of characteristics might make it the correct selection.